Network node with integrated power distribution

ABSTRACT

A control network comprises a plurality of network nodes arranged in a plurality of tiers, with first-tier nodes and lower tier nodes. A master control bus interconnects the first-tier nodes, which are also connected to a power source. Lower-tier buses interconnect groups of the lower tier nodes. The lower-tier buses include both data lines and a power source line derived from the power source, allowing the lower tier nodes to selectively distribute power to local loads. A first-tier node may be embodied as a hub controller configured to be connected to one or more of said lower-tier buses. The hub controller may comprise a plurality of internal hub nodes (including a hub master node and hub slave nodes) integrated within the same physical unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 12/757,811filed Apr. 9, 2010, which is a continuation of U.S. application Ser. No.11/046,539 filed Jan. 28, 2005, now U.S. Pat. No. 7,724,778, which ishereby incorporated by reference as if set forth fully herein.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The field of the present invention generally relates to control networksand related methods for configuring and operating control networks.

2) Background

Automated control systems are commonly used in a number ofmanufacturing, transportation, and other applications, and areparticularly useful for controlling machinery, sensors, electronics, andother system components. For example, manufacturing or vehicular systemsmay be outfitted with a variety of sensors and automated electricaland/or mechanical parts that require enablement or activation whenneeded to perform their assigned functions. Such systems commonlyrequire that functions or procedures be carried out in a prescribedorder or with a level of responsiveness that precludes sole reliance onmanual control. Also, such systems may employ sensors or othercomponents that require continuous or periodic monitoring and thereforelend themselves to automated control.

As the tasks performed by machinery and electronics have grown in numberand complexity, a need has arisen for ways to exercise control over thevarious components of a system rapidly, efficiently and reliably. Thesheer number of system components to be monitored, enabled, disabled,activated, deactivated, adjusted, or otherwise controlled can lead tochallenges in designing and implementing sophisticated control systems.As the number of controlled components in a system increases, not onlydo control functions become more complicated, but also the wiring orinter-connections of the control system become more elaborate andcomplex. A robust, scalable control system is therefore needed.

In addition, increasing reliance on automated control in various fieldshas resulted in more significant potential consequences if the automatedcontrol system fails. Therefore, a need exists for a reliable controlsystem that is nevertheless capable of controlling large systems ifnecessary.

Traditionally, control systems in certain applications, such as transitvehicles and railcars, have relied upon relay-based control technology.In such systems, relays and switches are slaved to a logic circuit thatserves to switch signal connections. This approach requires a largenumber of relays and a substantial amount of wiring throughout thevehicle. A typical transit car may be outfitted with hundreds of poundsof wiring and related electronic components. Wiring for conventionalcontrol systems can be expensive, both from a material standpoint and alabor standpoint (to layout the wiring throughout the vehicle).Conventional control systems can also be costly to maintain anddiagnose, especially where wiring is complicated and profuse.

Substantial improvements in the field of automated control in general,and vehicular control in particular, are described in, for example, U.S.Pat. Nos. 5,907,486, 6,061,600, 6,094,416, 6,147,967, and 6,201,995,each of which is assigned to the assignee of the present invention, andeach of which is hereby incorporated by reference as if set forth fullyherein.

In many network settings, the controlled machinery, sensors,electronics, and other system components require electronic power tooperate. Often power cables or wires are run independently throughoutthe controlled network in order to feed power to the various systemcomponents. The power distribution system therefore may lead to a secondnetwork of wires within the system (e.g., vehicle), which may, amongother things, complicate layout, diagnosis, and maintenance of thenetwork.

Accordingly, it would be advantageous to provide a system, architecture,and/or method that overcomes one or more of the foregoing problems,disadvantages, or drawbacks.

SUMMARY OF THE INVENTION

The invention in one aspect is generally directed to control networksand to methods for configuring and operating networks for control, powerdistribution, and other applications.

In one aspect, a control network comprises a plurality of network nodesarranged in a plurality of tiers, the nodes including first-tier nodesand lower tier nodes. A master control bus interconnects the first-tiernodes, and a power source (for distributing relatively high powerthroughout the control network) is electronically coupled to thefirst-tier nodes. One or more lower-tier buses interconnect groups ofthe lower tier nodes. The lower-tier buses preferably include both datalines and a power source line derived from the power source. The lowertier nodes selectively distribute power from the power source line tolocal loads, by way of, e.g., controllable switches.

In various embodiments, a first-tier node may be embodied as a hubcontroller configured to be connected to one or more of said lower-tierbuses. The hub controller may comprise a plurality of internal hub nodesintegrated within the same physical unit. The internal hub nodes maycomprise a hub master node adapted to interface with other first tiernodes over the master control bus, and one or more hub slave nodesadapted to interface with lower tier nodes using one of the lower-tierbuses.

Further embodiments, variations and enhancements are also disclosedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of a master-slave control network fordistributing control and power signals throughout the network.

FIG. 2 is a high level diagram illustrating a hierarchy in accordancewith one example of a master-slave control network.

FIG. 3 is a diagram showing one embodiment of a power/data hub as may beused, for example, in the control network of FIG. 2 or otherwise.

FIG. 4 is a diagram illustrating a master and slave nodes along withdistribution of various power and data signals.

FIG. 5 is a more detailed block diagram of a power/data hub showing onepossible internal arrangement of hub components.

FIGS. 6A and 6B are diagrams illustrating possible alternativeconfigurations for connection of a hub controller to various remotenetwork nodes.

FIG. 7 is a block diagram of one embodiment of a network node, showingpower and signal connections to various destinations.

FIG. 8 is a more detailed diagram of an example of a network node as maybe constructed in accordance with the basic architecture of FIG. 7,showing further possible implementation details.

FIG. 9A is a diagram of one possible network node housing, and FIGS. 9Band 9C are exploded view diagrams showing two possible techniques forconstructing and assembling the housing of FIG. 9A.

FIGS. 10 and 11 are diagrams illustrating cross-sectional views inaccordance with different variations of the network node housingillustrated in FIG. 9A.

FIG. 12 is a diagram showing one possible technique for physicallyconnecting a network node, such as shown in FIG. 9A, within a controlnetwork.

FIG. 13 is a diagram of an alternative embodiment of a hub controllerfor use in a control network for distributing power and data signals.

FIGS. 14A and 14B are oblique and top view diagrams, respectively, of ahub controller of the type illustrated, for example, in FIG. 5, and FIG.14C is an assembly diagram showing one possible technique forconstructing and assembling the hub controller of FIGS. 14A and 14B.

FIGS. 15A through 15F are more detailed diagrams of one possibleembodiment of a network node in general accordance with the principlesillustrated in and described with respect to FIG. 9A.

FIG. 16 is a block diagram illustrating the relative placement ofnetwork hubs and nodes of a control network within a vehicleenvironment.

FIG. 17 is a diagram of an alternative embodiment of a network nodesimilar to the network node illustrated in FIGS. 15A through 15F.

FIG. 18 is a schematic block diagram of a network node according to oneembodiment as disclosed herein.

FIG. 19 is a schematic block diagram of a network node according toanother embodiment as disclosed herein, adapted for use in a two fiberring network.

FIG. 20 is a diagram of a master-slave two-fiber ring network, showingcertain node details, as may be used in connection with variousprinciples and techniques described or illustrated herein.

FIG. 21 is a diagram of another embodiment of a power/data hub asdisclosed herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a conceptual diagram of a master-slave control network 100 fordistributing control signals and power throughout the network 100 tovarious destinations. In the example shown in FIG. 1, the network 100comprises a plurality of interconnected network hubs 102, 104, each ofwhich may be connected to one or more nodes 114 over a variety ofadditional buses 115. The network hubs 102, 104 preferably areinterconnected in a loop or ring configuration via a main bus 105 (whichmay comprise a number of bus segments interconnected between the variousnetwork hubs 102, 104 as illustrated). The network hubs 102, 104 may bephysically arranged such that each of the network hubs 102, 104 controlsa zone or general physical region of the instrumentality beingcontrolled and/or supplied with power. Depending upon configuration andimplementation, the network 100 may be used to control, e.g., vehicles,factories, buildings, robotic machinery, airplanes or other aircraft,ships or other watercraft, satellites, and so on.

In the example where the network hubs 102, 104 are connected in a loopor ring configuration, the main bus 105 preferably comprises one or moreoptical fibers which connect the various network hubs and carry data. Insuch an embodiment, each network hub 102, 104 may transmit a modulatedoptical signal having a frequency (or frequencies) that can be detectedby downstream nodes. Data is transmitted from an originating hub 102,104 to a destination hub by passing through each intervening hub alongthe main bus 105. The network hubs 102, 104 may support eitherunidirectional or bidirectional communication. As will be described inmore detail in connection with various embodiments disclosed herein,power is preferably distributed over buses 115 (using, e.g., power wiresbundled with data lines) and then locally applied to various loads bythe nodes 114.

In a preferred embodiment, the control network 100 of FIG. 1 forms amulti-tier, hierarchical control architecture allowing flexible controland monitoring of the various network nodes 114. The control network 100preferably includes both a top-tier master hub 102 (designated “M” inFIG. 1) and one or more top-tier slave hubs 104 (designated S1, S2 andS3 in this example, although there may be any number of slave hubs). Themaster hub 102 may control the various slave hubs 104, which in turncontrol the various lower-tier nodes 114.

FIG. 2 is a diagram illustrating a multi-tier, hierarchical controlnetwork 200 in accordance with one embodiment disclosed herein, and withthe general principles of FIG. 1. As illustrated in FIG. 2, and similarto FIG. 1, the control network 200 comprises a plurality ofinterconnected network hubs 202, 204, each of which may be connected toone or more nodes 214 over a variety of additional buses 215. Althoughdepicted as a single solid line in FIG. 2, the main bus 205 may comprisea fiber optic loop or ring as shown in FIG. 1, interconnecting thenetwork hubs 202, 204.

As with FIG. 1, the control network 200 preferably includes both atop-tier master hub 202 (designated “M” in FIG. 2) and a plurality oftop-tier slave hubs 204 (designated “Si”, “S2” and “S3” in this example,although there may be any number of slave hubs). The top-tier master hub202 may comprise a hub master node 232 (designated “HM” in FIG. 2) andone or more hub slave nodes 234 (designated “HS” in FIG. 2). Each of thetop-tier slave hubs 204 may likewise comprise a hub master node 252(also designated “HM”) and one or more hub slave nodes 254 (alsodesignated “HS”). Each of the hub slave nodes 234, 254 may be coupled toone or more network nodes 214 over additional buses 215. In a preferredembodiment, the hub slave nodes 234, 254 act in the capacity of a masterwith respect to the network nodes 214 to which they are coupled.

In one aspect, the control network 200 may comprise a multi-tiermaster-slave hierarchical control network. In a first tier, the top-tiermaster hub 202 (“M”) generally controls the top-tier slave hubs 204(i.e., “S1”, “S2” and “S3”), and thereby indirectly controls the variousnetwork nodes 114. At a second tier, internal to the top-tier master hub202, the hub master node 232 (“HM”) controls (i.e., acts as asecond-tier master with respect to) the hub slave nodes 234 (“HS”).Likewise, also at a second tier, and internal to the top-tier slave hubs204, the hub master node 252 (“HM”) controls (i.e., acts as asecond-tier master with respect to) the hub slave nodes 254 (“HS”). At athird tier, each of the hub slave nodes 234, 254 may control (i.e., actas a third-tier master with respect to) the various network nodes 214(i.e., third-tier slave nodes) to which they are coupled. Thus, the hubmaster nodes 232, 252 may serve a dual role, acting both as first-tierslave nodes and second-tier master nodes. Likewise, the hub slave nodes234, 254 may also serve a dual role, acting both as second-tier slavenodes and third-tier master nodes. The resulting architecture may beviewed as a hierarchical, multi-tier master-slave control network.

According to one embodiment, each of the network hubs 202, 204 mayinclude a variety of functionality, including an interface for inter-hubcommunication, an interface for communication to multiple slave nodes(i.e., network nodes 214), and a mechanism for distributing power (bothlow power and high power) to the various network nodes 214. According toa particular configuration, low power may be generally associated withthe voltage level required by digital or logic circuitry, while highpower may generally be associated with a voltage level higher than thatrequired by the digital or logic circuitry. For example, low power maycorrespond to 5 volts, while high power may correspond to 12 or 24volts.

Aspects of a preferred network hub are illustrated in FIGS. 3, 4 and 5.FIG. 3 is a diagram showing one embodiment of a power/data hub 300 asmay be used, for example, as a network hub in the control network 100 or200 or any other suitable network architecture. In FIG. 3, thepower/data hub 300 is physically constructed of housing 301 having anouter shell or casing, and capable of connecting to a variety of buses.The power/data hub 300 in this example connects to a main control buscable 308 (corresponding to, e.g., main control bus 105 or 205) througha bus terminal connector 306 which connects to a main bus connector 305of the power/data hub 300. Similarly, various other bus cables(corresponding to additional buses 115 or 215 in FIG. 1 or 2, anddepicted as signal lines 327 in FIG. 3) may be connected to busconnectors 325 of the power/data hub 300. A main power cable 318 mayalso be connected to the power/data hub 300 through a power terminalconnector 316 which connects to a main power connector 315 of thepower/data hub 300. In alternative embodiments, the main power cable 318may be bundled or integrated with the main bus cable 308, and only asingle bus/power connector could then be used (unless additionalconnectors are desired for ring/loop configuration or redundancy, aspreviously explained). The additional bus cables 327 may include abundled or integrated power cable for distributed power to variousnetwork nodes (e.g., nodes 114 or 214 in FIG. 1 or 2), or alternativelya separate power cable may be provided running adjacent to the buscables 327, for providing power to the network nodes.

In other embodiments, the power/data hub 300 includes a second main busconnector 305 to facilitate the connection of the main bus in a loop orring configuration. FIG. 21 illustrates an embodiment of a power/datahub 2100 similar to that shown in FIG. 3, wherein components labeledwith reference numerals “21xx” in FIG. 21 generally correspond tocomponents in FIG. 3 labeled with reference numerals “3xx”, butillustrating two main bus cables 2108 connected to two main busconnectors 2105 of the power/data hub 2100. Alternatively, the maincontrol bus cable 308 may be split, with signals being thereby connectedto two (or more) different destinations. Also, in any of the foregoingembodiments, redundant bus cables may be provided to allow a dual-loopconfiguration, providing additional backup in case of a break in thecable or connection failure. A particular example of a dual-looparchitecture is illustrated in FIG. 20, described later herein.

The physical shape of power/data hub 300 in FIG. 3 may be conducive toallowing multiple bus connections. In this particular example, thehousing 301 is hexagonally shaped, allowing convenient bus connectionson each of the six sides of the housing 301. Other shapes for thehousing 301 may also be utilized—for example, square, pentagonal,octagonal, etc.; also the side corners may be rounded if desired. Thebottom side (not visible in FIG. 3) of the housing 301 may be used formounting the housing 301 to a solid frame or other surface, such as theframe of a bus, railcar, or vehicle. The top side 311, or any othersuitable location, of the housing 301 may advantageously be outfittedwith a user interface, in this example comprising a display 330 and aset of manual controls 332 (which may be embodied as buttons, knobs,switches, etc., or any combination thereof). The display 330 may providea graphical indication of status information, and allow programming of,e.g., various node functions or monitoring parameters. In the exampleshown in FIG. 3, the display 330 identifies the power/data hub 300 as“Hub No. 3,” and provides a status readout of each of the internal nodes(i.e., the hub master node and hub slave nodes). Using the manualcontrols 332, the power/data hub 300 may be further configured todisplay the status of individual network nodes relating to each of thehub nodes, to the extent that information is available at the power/hubnode 300. The manual controls 332 may also be used to set certainfeatures of functions of the various hub nodes or network nodes (e.g.,to select which loads the network nodes should supply power to), toselect what nodal parameters to monitor, and so on.

FIG. 13 illustrates an alternative embodiment of a power/data hub 1300as may be used, for example, as a network hub in the control network 100or 200 or any other suitable network architecture. In FIG. 13, as withFIG. 3, the power/data hub 1300 is physically constructed of housing1301 having an outer shell or casing, and capable of connecting to avariety of buses. The power/data hub 1300 in this example is generallybox-shaped, and connects to a main control bus cable 1308 (correspondingto, e.g., main control bus 105 or 205) through a main bus connector1305. As described with respect to FIG. 3, a second main bus connectormay be included to facilitate connection in a loop or ringconfiguration, and additional main bus connectors may be added for aredundant main control bus cable if desired. Other bus cables 1327(corresponding to, e.g., additional buses 115 or 215 in FIG. 1 or 2) maybe connected to bus connectors 1325 of the power/data hub 1300. A mainpower cable 1318 may also be connected to the power/data hub 1300through a main power connector 1315. In alternative embodiments, themain power cable 1318 may be bundled or integrated with the main buscable 1308, and only a single bus/power connector could then be used(unless additional connectors are desired for ring/loop configuration orredundancy, as previously explained). The additional bus cables 1327 mayinclude a bundled or integrated power cable for distributed power tovarious network nodes (e.g., nodes 114 or 214 in FIG. 1 or 2), oralternatively a separate power cable may be provided running adjacent tothe bus cables 1327, for providing power to the network nodes.

FIG. 4 is a diagram showing further configuration details includingvarious power and data signals as may be provided by a hub controller400 (such as power/data hub 300 or any of the other alternative hubcontroller embodiments described herein). In FIG. 4, a hub master node402 (generally corresponding to hub master node 302 in FIG. 3) iscommunicatively coupled to various hub slave nodes 404 (generallycorresponding to hub slave nodes 304 in FIG. 3) via a hub data bus 405,which preferably comprises a high speed data bus internal to the hubcontroller. The hub nodes 402, 404 are preferably housed within a hubcontroller enclosure such as housing 301 illustrated in FIG. 3, forexample. The hub master node 402 connects to a main control bus 408,which may connect to additional hub controllers (not shown). Each of thehub slave nodes 404 may connect to various downstream network nodes (notshown in FIG. 4) through cables or other connection means, representedcollectively as lines 427 in FIG. 4, including a high power output line442, a low power output line 441, and a data bus 440 (which may be aparallel or serial data bus). The hub controller 400 preferably includesa power conversion unit 420 for converting incoming high power to lowpower for distribution over low power output lines 441. The lower poweroutput may alleviate the need for downstream network nodes to performtheir own power conversion or to receive low power wires from some othersource. The hub controller 400 may directly provide the incoming highpower signal 418 to the high power output lines 442 of the various otherbuses 427, subject to any type of current control or shutoff mechanism,or other safety circuitry, as may be desired. In this manner, both highand low power may be provided to the various network nodes connected tothe hub controller 400.

FIGS. 6A and 6B are diagrams showing details of possible alternativeconfigurations for connection of a hub slave node of a hub controller tovarious other network nodes, in a manner allowing the hub slave node ofthe hub controller to provide both data information and powerselectively to various remote loads. In both examples of FIGS. 6A and6B, redundant parallel data buses are utilized to increase reliability,although only a single data bus may be used in alternative embodiments.In FIG. 6A, a hub controller 602, which may be embodied as, e.g.,power/data hub 302 in FIG. 3 or 402 in FIG. 4, communicates with variousnetwork nodes 604 over parallel data buses 610, 611 (which may compriseelectrical wires and/or optical fibers). The hub controller 602 alsoprovides low power signal line(s) 612, as well as a high power signalline 614, to the various network nodes 604. An additional high powerline may be provided for the return path for the high power line 614, orelse the return path may be through a grounded connection. Each of thenetwork nodes 604 may control a number of local loads (including suchthings as motors, lights, switches, etc.). Each network node 604 mayprovide various input/output control signals 620 for interacting withlocal components in a conventional manner—for example, for turning on oroff various components, checking status information, and the like. Eachnetwork node 604 also is capable of distributing high power to the localloads through power control lines 625 (generically designated “L1”through “LN” in FIG. 6A for controlling up to N local loads). Onepossible node configuration for supplying power to various local loadsis illustrated in FIG. 7, described later herein.

FIG. 6B illustrates another possible configuration for connecting of ahub slave node of a hub controller to various network nodes, in a mannerallowing the network node to selectively provide power to various localloads. The configuration of FIG. 6B is generally configured in adaisy-chain arrangement, but may also be suited for a ring or loopconfiguration if the last node connects back to the hub controller. Aswith FIG. 6A, redundant data buses are utilized to increase reliability,although only a single data bus may be used if desired. In FIG. 6B, ahub controller 652, which may be embodied as, e.g., power/data hub 302in FIG. 3 or 402 in FIG. 4, communicates with various network nodes 654over data buses 660, 661 (which may comprise electrical wires and/oroptical fibers). Data signals are propagated along the various segmentsof data buses 660, 661 via the intervening network nodes 654. The hubcontroller 652 also provides low power signal line(s) 662, as well as ahigh power signal line 664, to the various network nodes 654. Theselines are propagated along each of the network nodes 654 as well. Aswith FIG. 6A, an additional high power line may be provided for thereturn path for the high power line 664, or else the return path may bethrough a grounded connection. Each of the network nodes 654 may controla number of local loads, and may provide various input/output controlsignals 670 for interacting with local components in a conventionalmanner—for example, for turning on or off various components, checkingstatus information, and the like. Each network node 654 also is capableof distributing high power to the local loads through power controllines 675 (generically designated “L1” through “LN” in FIG. 6B forcontrolling up to N local loads). One possible node configuration forsupplying power to various local loads is similar to FIG. 7, describedlater herein, but with a pass-through communication interface (similarto that shown in FIG. 19 or 20, for example), allowing signals to bepropagated (with manipulation or error detection if desired) along thechain of network nodes 654.

Additional details will now be described concerning a preferred hubcontroller configuration. FIG. 5 is a block diagram illustrated onepossible arrangement of internal hub components of a power/data hub 500,and represents a potential embodiment of power/data hub 302 or 402. InFIG. 5, a hub master node 502 (generally corresponding to hub masternode 302 in FIG. 3 or 402 in FIG. 4) is communicatively coupled tovarious hub slave nodes 504 (generally corresponding to hub slave nodes304 in FIG. 3 or 404 in FIG. 4) via a hub data bus 505, which preferablycomprises a high speed data bus internal to the hub controller 500. Thehub nodes 502, 504 are preferably housed within a hub controllerenclosure or housing such as 301 in FIG. 3. The hub master node 502connects to a main control bus 508, which may connect to additional hubcontrollers (not shown). Each of the hub slave nodes 504 may connect tovarious downstream network nodes (not shown in FIG. 5) through cables orother connection means, represented collectively as lines 518 in FIG. 5.These connections may include a high power output line 542, a low poweroutput line 541, and a data bus 540 (which may be a parallel or serialdata bus). The hub controller 500 preferably includes a power conversionunit 520 for converting incoming high power to low power fordistribution over low power output lines 541, and also for providing lowpower locally to the various hub nodes 502, 504. The hub controller 500may directly provide the incoming high power signal 518 to the highpower output lines 542 of the various other buses 518, subject to anytype of current control or shutoff mechanism, or other safety circuitry,as may be desired. As with FIG. 4, in this manner both high and lowpower may be provided to the various network nodes connected to the hubcontroller 500.

The hub controller 500 may include an internal high power bus 562 andinternal low power bus 562 for distributing high and low power,respectively, to the various downstream networks controlled by the hubslave nodes 504. In the situation where the hub controller 500 connectsto two main data bus segments, the hub master node 502 may be connectedto two output ports instead of a single one as illustrated in FIG. 5. Inaddition, any one of the hub nodes 502, 504, but preferably the hubmaster node 502, may include an interface for receiving command inputs550 and outputting display data 551 to an external display (such asdisplay 330 illustrated in FIG. 3).

FIGS. 14A, 14B and 14C illustrate additional details of one possiblephysical implementation of a hub controller similar to power/data hub302 illustrated in FIG. 3. FIG. 14A shows an oblique view of a hubcontroller 1400, while FIG. 14B shows a top view thereof. FIG. 14C is anassembly diagram illustrating the various components that may be used toform the hub controller 1400 depicted in FIGS. 14A and 14B.

Turning first to FIG. 14A, a hub controller 1400 may comprise a housing1402 of generally octagonal shape, although it may alternatively take onother shapes and sizes as mentioned previously with respect to FIG. 3.The housing 1402 may be constructed of any suitable material, and maycomprise a rugged lightweight material such as aluminum that providesenvironmental protection and allows for heat dissipation. In other typesof control environments, different types of housings or materials (suchas plastic, ceramics, metal composites, or any combination thereof) maybe used. The housing 1402 may encase the circuitry and electronics ofthe hub controller 1400, including the various hub nodes (such as, e.g.,hub nodes 302, 304 illustrated in FIG. 3). As further illustrated inFIGS. 14A and 14C, the housing 1402 may have heat dissipating members(e.g., fins) 1459 to facilitate cooling of the hub controller 1400. Thehousing 1402 may include a top housing plate 1451 and a bottom housingplate 1452, each of which is secured to a center housing frame 1401 byany suitable fastening means, such as screws 1465 and 1466. In theparticular example illustrated, the bottom housing plate 1452 includestabs 1455 allowing the hub controller 1400 to be conveniently mounted toa vehicle frame or other appropriate surface with suitable fasteningmeans, such as screws.

Around the perimeter of the center housing frame 1401, along eachindividual sidewall, are bus connectors 1470 preferably designed toallow ready coupling of network power/data cables (not shown). The busconnectors 1470 in this particular embodiment allow for bundling ofpower and data lines in a single cable. Accordingly, each bus connector1470 includes one or more power line connector(s) 1471 (for high power),as well as a variety of data line connectors 1472, 1473 (which mayconnect both data and low power in certain embodiments). Cablesconnected to bus connectors 1470 may carry both data signals and powerto various downstream network nodes (not shown in FIGS. 14A-14C). Thebus connector for the main control bus may have a similar bus connector1470, or else may comprise a different set of signal connectorsdepending upon the nature of the main control bus. Inter-hub cables usedto connect various hub controllers may need to be thicker than thecables connected to other network nodes, as they may have a larger powerdraw (depending upon the system configuration).

According to certain embodiments, bus connectors 1470 are connected toother hubs or nodes using a split cable (not shown), with the high powerline connectors 1471 in this example being split different directions,and with data line connectors 1472, 1473 also being split differentdirections. Such a configuration facilitates connection of the varioushubs and nodes in a loop or ring architecture. When a hub master orslave node (e.g., 502 or 504 shown in FIG. 5) is in a listening mode, itmay pass through signals received via data line connectors 1472 to theother data line connectors 1473 for propagation to the next hub or nodedownstream, and vice versa. This action allows signals to be transmittedaround a ring or loop of hubs or nodes. When a hub master or slave nodeis in an active transmission mode, it may transmit signals bothdirections—i.e., using both data connectors 1472, 1473. Further possibletechniques relating to ring or loop communication, as may be used inconnection with hub controller 1400, are described with respect to FIGS.18-20 later herein.

Although not illustrated in FIGS. 14A-14C, the top housing plate 1451(or any other suitable portion) of the hub controller 1400 may includemanual controls and/or a display, similar to the power/data hub 302illustrated in FIG. 3.

Additional details will now be provided concerning various possibleembodiments of network nodes as may be used in connection with variousembodiments as described herein. FIG. 7 is a block diagram of oneembodiment of a network node 700, showing power and signal connectionsto various destinations. In the particular example of FIG. 7, thenetwork node 700 transmits and receives data signals over data buses710, 711, and receives a high power input line 714 and a low power inputline 712. Data buses 710, 711, high power input line 714, and low powerinput line 712 may be connected upstream to a hub controller or,depending upon the system configuration, may be connected to an upstreamnode or series of nodes which eventually reach the hub controller. Thenetwork node 700, among other things, selectively provides high power tovarious loads (designated as “L1”, “L2” and “L3” in FIG. 7). The networknode 700 may also receive input signals 722 and generate output signals721 in a conventional manner to control, monitor or otherwise interactwith various network components. If arranged in a daisy chainconfiguration, or otherwise desired, the network node 700 may passthrough the high power input line 714 as an output, and may likewisepass through the low power input line 712 as an output 732.

As further illustrated in the example shown in FIG. 7, the network node700 comprises a communication interface 740, a controller 745, aninput/output interface 749, and a set of high power switches (designated“SW1”, “SW2”, and “SW3” in FIG. 7). The communication interface 740 isresponsible for communicating with the hub controller and/or theupstream or downstream network nodes. The bus connections to thecommunication interface 740 depend upon the system architecture. In thisexample, the two data buses 710 and 711 may generally correspond to databuses 610 and 611 depicted in FIG. 6A. In a configuration such as shownin FIG. 6B, two additional data bus connections may be provided withcommunication interface 740. Control of the network node 700 isgenerally provided by controller 745, which may comprise, e.g., amicroprocessor or other suitable circuitry or electronics. Thecontroller 745 interprets any commands received via the communicationinterface 740, and responds as necessary by transmitting responsive dataor information via communication interface 740 to the appropriatedestination. The controller 745 is also preferably responsible fortransmitting the various output signals 721 and receiving andinterpreting the various input signals 722, via input/output interface749.

The controller 745 also preferably responds to commands received fromthe hub controller or otherwise (e.g., an upstream node or programmed byway of manual controls) to selectively provide power to the variousloads L1, L2 and L3. In response to received commands, the controller745 selectively actuates switches SW1, SW2 and SW3, thereby connectingpower to or disconnecting power from the individual loads L1, L2 and L3.The controller 745 may also monitor the status of the switches SW1, SW2and SW3, and record or report this information to the hub controller oran upstream node.

FIG. 8 is a more detailed diagram of an example of a network node 804 asmay be constructed in accordance with the basic architecture of FIG. 7,showing further possible implementation details. As shown in FIG. 8,this particular network node 804 includes redundant processors 850, 851(which may be embodied as conventional microprocessors) acting as thecontroller for the network node 800, in order to, e.g., increasereliability. The communication interface of the network node 804comprises a first transceiver 860 for communicating over the first databus 810 (“channel A”), and a second transceiver 861 for communicatingover the second data bus 811 (“channel B”). A channel selection circuit862 selects between incoming signals received by transceivers 860, 861.Similar signals may be received over data buses 810, 811 when, e.g., thedata buses 810, 811 are being used for redundant communication, or whenthe node 804 is configured with other nodes (typically including a hub)in a ring or loop configuration. In the case where similar signals maybe received over both data buses 810, 811, the channel selection circuit862 arbitrates and may, for example, select the best quality signal.

The node 804 may comprise an internal bus 865 for facilitatingcommunication by processors 850, 851 with other node components, such aschannel selection circuit 862. The processors 850, 851 may utilize adual port random-access memory (RAM) 853 to facilitate processing, and,if desired, to allow communication between the two processors 850, 851.The processors 850, 851 interpret any commands received via data buses810, 811, and respond as necessary by transmitting responsive data orinformation via the data buses 810, 811. The processors 850, 851 arealso preferably responsible for transmitting the various output signals821 and receiving and interpreting the various input signals 822 fromdevices under control or being monitored by the node 804. As theprocessors 850, 851 are intended to be redundant, each of the processors850, 851 has a set of input/output signals 855 and 856, respectively, asubset of which include switch control signals 857 and 858. Outputsignals from either processor 850, 851 may drive the node output signals821 (via logic gates 871), while input signals 822 are sent to bothprocessors 850, 851. Similarly, switch control signals 857, 858 arecombined by logic gates 875, 876, 877, allowing either processor 850,851 to control the switches 881, 882, 883, and thereby provide power tovarious loads.

Similar to the node in FIG. 7, the processors 850, 851 preferablyrespond to commands received from the hub controller or otherwise (e.g.,an upstream node or programmed by way of manual controls) to selectivelyprovide power to the various loads by selectively actuating switches881, 882, 883 (also designated SW1, SW2 and SW3 in FIG. 8), therebyconnecting power to or disconnecting power from the individual loads.Switches 881, 882, 883 may be embodied as, e.g., high power transistors(such as high power FETs). The processors 850, 851 may also monitor thestatus of the switches SW1, SW2 and SW3, and record or report thisinformation to the hub controller or an upstream node. Although threeswitches SW1, SW2 and SW3 are illustrated in FIG. 8, any number ofswitches may be present.

According to certain embodiments, data buses 810, 811 are connected totwo different nodes (one of which may be a hub), and transmit and/orreceive signals propagated around a ring or loop. When the node 804 isin a listening mode, it may pass through signals received by data bus810 to the other data bus 811, and vice versa. This action allowssignals to be transmitted around a ring or loop of hubs or nodes. Whenthe node 804 is in an active transmission mode, it may transmit signalsboth directions—i.e., using both data buses 810, 811. Further possibletechniques relating to ring or loop communication, as may be used inconnection with node 804, are described with respect to FIGS. 18-20later herein.

Although not illustrated in FIG. 8, the node 804 may also receive a lowpower source line from an upstream hub or node (as previously describedwith respect to FIG. 7), and may propagate the low power source line toa downstream node.

The various network nodes as described herein (e.g., in FIG. 7 or 8) maybe physically constructed in a variety of different manners. FIG. 9Ashows one possible network node housing 901 for a node 900, generallycylindrical in shape, and having two mating semi-cylindrical plates 916,917 that may be assembled as depicted in FIG. 9C. Alternatively, thehousing 901 may comprise semi-cylindrical plates 976, 977 with separateend pieces 975, 985, as illustrated in FIG. 9B (with certain detailssuch as cable connections omitted). The node housing 901 in the exampleof FIG. 9A has two bus connectors 907 on opposite sides of the nodehousing 901, each of which is adapted to receive a cable 908 containingsignal lines that are carried from node to node. The node housing 901also includes one or more input/output line connectors 917 forconnecting to various input/output lines 918, allowing the node 900 tocontrol various local devices.

As depicted in FIG. 9C, the top and bottom plates 916, 917 of the nodehousing preferably have narrow cutouts 926 and 927, respectively, whichalign together and conform to the shape of high power transistors(typically high power field effect transistors or FETs) which mayprovide output power to various local devices. The high powertransistors may be one possible embodiment of switches SW1, SW2, SW3 asdepicted in FIG. 7 or 8. The high power transistors may be attached to acircuit board internal to the node housing 804. Two possibleconfigurations of attaching and securing the high power transistors areillustrated in FIGS. 10 and 11. FIG. 10 illustrates a cross-sectionalview of a node housing 1004 encasing a circuit board 1040 which may besecured to the node housing 1004 in part by internal cutout groovesinside the node housing 1004. High power transistors 1041, 1042 areattached to the circuit board 1040, and may be positioned such that theyare secured in part by being clamped within the gaps defined by cutouts926, 927 in FIG. 9C. Preferably the gaps defined by cutouts 926, 927conform to the contours of high power transistors 1041, 1042, so that nobreak in the seal of the housing plates 916, 917 occurs.

FIG. 11 illustrates a cross-sectional view of another node housing 1104showing another possible means for attaching and securing high powertransistors within the node housing 1104. As shown in FIG. 11, a circuitboard 1140 is mounted perpendicularly with respect to the plane wherethe two facing housing plates 916, 917 meet. The circuit board 1140 maybe secured to the node housing 1104 in part by internal cutout groovesinside the node housing 1104, as illustrated. High power transistors1141, 1142 are attached to the circuit board 1140 via legs 1151, 1152,and, as with FIG. 10, may be positioned such that they are secured inpart by being clamped within the gaps defined by cutouts 926, 927 inFIG. 9C. Preferably the gaps defined by cutouts 926, 927 conform to thecontours of high power transistors 1141, 1142, so that no break in theseal of the housing plates 916, 917 occurs.

In the examples of FIGS. 9A-9C, 10 and 11, the node housing 904, 1004 or1104 may provide significant advantages for dissipation of heatgenerated by the high power transistors. The node housing 904 is thuspreferably constructed of a lightweight material such as aluminum thatprovides environmental protection and allows for heat dissipation,although different types of housings or materials (such as plastic,ceramics, metal composites, or any combination thereof) may be used inwhole or part. The contact of the high power transistors 1041, 1042 or1141, 1142 with the node housing 904, 1004 or 1104 helps facilitatetransfer and dissipation of heat generated by the high powertransistors.

FIG. 12 is a diagram showing one possible technique for physicallyconnecting a network node, such as shown in FIG. 9A (or FIG. 10 or 11),within a control network. As illustrated in FIG. 12, a node 1201 isphysically attached to a cable harness 1214 by any suitable securingmeans such as straps 1299 that may be comprised of, e.g., heavy dutyduct tape, vinyl, fabric, rubber, or any other appropriate material. Buscables 1208 may connect to both sides of the node 1201, and may likewisebe strapped or otherwise physically bundled with the cable harness 1214.A large number of nodes 1201 may thereby be conveniently dispersedthroughout a network environment, using pre-existing cabling paths.

FIGS. 15A through 15F are more detailed diagrams of one possibleembodiment of a network node in general accordance with some of theprinciples illustrated in and described with respect to, e.g., FIGS. 9A,10 and 11. As illustrated in FIG. 15A, a node 1500 comprises a nodehousing 1501 which may, as with the node 900 illustrated in FIG. 9, beconstructed of two opposing plates 1516, 1517 (see FIG. 15F) which areclammed together. The node housing 1501 may, as before, be constructedof a lightweight material such as aluminum that provides environmentalprotection and allows for heat dissipation, although different types ofhousings or materials (such as plastic, ceramics, metal composites, orany combination thereof) may be used in whole or part. The node housing1501 may also be constructed with heat dissipating fins 1559, which areperhaps best illustrated in the cross-sectional view of FIG. 15E. Thenode housing 1501 of FIG. 15A is generally cylindrical in shape, and maybe deployed within a network environment in a manner similar to thatdepicted in FIG. 12, for example.

The node housing 1501 may further comprise a pair of end plates 1575,1585, such as illustrated in FIG. 15F, each of which has various signalconnectors as will be described. On one end plate 1575, as illustratedin FIGS. 15A, 15C and 15F, a bus connector 1570 may be provided forconnection to other nodes (including a hub). The bus connector 1570 mayinclude one or more power line connector(s) 1571 (for high power), aswell as a variety of data line connectors 1572, 1573 (which may connectboth data and low power in certain embodiments). The bus connector 1570,power line connector(s) 1571, and data line connectors 1572, 1573 mayall have a similar function to components 1470, 1471, 1472 and 1473described earlier with respect to FIGS. 14A-14C. One or more cablesconnected to bus connector 1570 may carry both data signals and powerfrom an upstream node (or hub) and to various downstream network nodes.According to certain embodiments, the bus connectors 1570 connects toother nodes (or a hub) using a split cable (not shown), with the highpower line connectors 1571 being split different directions, and withdata line connectors 1572, 1573 also being split differentdirections—e.g., upstream and downstream. Such a configurationfacilitates connection of a plurality of nodes in a loop or ringarchitecture. When the node 1500 is in a listening mode, it may passthrough signals received of data line connectors 1572 to the other dataline connectors 1573 for propagation to the next hub or node downstream,and vice versa. This action allows signals to be transmitted around aring or loop of nodes. When the node 1500 is in an active transmissionmode, it may transmit signals both directions—i.e., using both dataconnectors 1572, 1573. Further possible techniques relating to ring orloop communication, as may be used in connection with node 1500, aredescribed with respect to FIGS. 18-20 later herein.

The node 1500 also may have various status indicators 1590 which areexternally visible so that the status of the node 1500 may beconveniently observed or monitored. The status indicators 1590 may beembodied as, e.g., light emitting diodes (LEDs) or other suitable means.More sophisticated status indication means, such as an LCD display, mayalso be used.

The other end plate 1585 of the node 1500, as illustrated in FIGS. 15Dand 15F, preferably comprises an input/output signal line connector 1580which is adapted to connect with various signal lines for controlling ormonitoring local devices. The node 1500 thus connects to the network viabus connector 1570 on one end of the node 1500, and to various localdevices via an input/output signal line connector 1580 on the other endof the node 1500.

As with the nodes illustrated in FIGS. 10 and 11, the node 1500 mayencapsulate a circuit board 1540 to which may be attached high powertransistors (e.g., FETs) 1541, 1542, as illustrated in FIGS. 15E and15F. The ends of high power transistors 1541, 1542 may be clampedbetween the top housing plate 1516 and bottom housing plate 1517 of thenode housing 1501. Fastening means such as screws 1565 not only serve tosecure together the top housing plate 1516 and bottom housing plate1517, but may also improve heat dissipation by increasing the heattransfer capability. As also illustrated in FIGS. 15E and 15F, thestatus indicators 1590 may also be attached to circuit board 1540.

FIG. 17 is a diagram of an alternative embodiment of a network node,similar to the network node illustrated in FIGS. 15A-15F. In FIG. 17,components identified with reference numerals “17xx” are generallyanalogous to the components in FIGS. 15A-15F identified with referencenumerals “15xx.” Thus, node 1700 comprises a housing 1701 preferablyconstructed of a top plate 1716 and bottom plate 1717 that are securedtogether by suitable fastening means such as screws 1765. The maindifference between the node 1700 in FIG. 17 and the one in FIGS. 15A-15Fis that node 1700 has identical end plates 1775 with the same type ofbus connector 1770 at each end of the node 1700. This configurationpermits daisy chaining of nodes using single power/data cable segments,without the need for a split cable if a ring or loop architecture isdesired. One of the bus connectors 1770 connects to an upstream node,and the other bus connector 1770 connects to a downstream node in thechain. Input/output signals may be connected to an input/output signalline connector (not shown) located at a suitable place on the housing1701.

FIG. 16 is a block diagram illustrating an example of the relativeplacement of network hubs and nodes of a control network 1601 within avehicle environment. As illustrated in FIG. 16, a vehicle 1600 isoutfitted with a control network 1601 comprising a number of hubcontrollers 1602, 1604 arranged in a loop or ring configuration(although other arrangements would also be possible). Preferably, thehub nodes include a master hub node 1602 and one or more slave hubcontrollers 1604, similar to the architecture described in FIG. 1 (withmaster hub node M and slave hub nodes S1, S2, S3) or FIG. 2 (with masterhub node 202 and slave hub noes 204). The hub controllers 1602, 1604 areconnected by cable segments 1605 which collectively comprise a maincontrol bus, as described with respect to FIGS. 1 and 2, for example.

Each hub controller 1602, 1604 may connect to one or more additionalbuses 1615 which in turn connect to various additional nodes 1614. Theoverall architecture of the control network 1601 may be a hierarchical,master-slave network architecture such as described previously withrespect to FIG. 1 or 2. The hub controllers 1602, 1604 may be embodiedas, e.g., any of the hub controllers or power/data hubs in FIG. 3, 5, or14A-14C, and the additional nodes 1614 may be embodied as, e.g., any ofthe nodes in FIGS. 9A-9C or 15A-15F.

In a preferred embodiment, the control network 1601 is divided intocontrol zones, which each of the hub controllers 1602, 1604 generallyresponsible for controlling a particular zone. The hub controllers 1602,1604 are preferably dispersed throughout the vehicle 1600 at locationscorresponding to their respective control zones. The lower tier nodes1614 (assuming a hierarchical architecture) are likewise dispersedthroughout the vehicle 1600, at locations which are physically proximateto the vehicle components or devices which they control or monitor.Preferably, the lower tier nodes 1614 can be programmed to determinewhether or not to supply power to local loads located near them, in amanner previously described. The control network 1601 thereby allowsdistribution of both control information and power throughout thevehicle 1600. The architecture of FIG. 16, and more generally of FIG. 1or 2, can greatly simplify wiring for a control network.

In a preferred embodiment, cables 1605 carry both high power among thevarious hub controllers 1602, 1604, and also carry data (e.g., controlinformation) over fiber optic lines. Similarly, cable buses 1615 carryboth high power among the various nodes 1614 and a hub controller 1602or 1604, and also carry data (e.g., control information) among them overfiber optic lines. The hub controllers 1602, 1604 are preferablyconfigured in a ring or loop architecture, so that if a cable is damagedor severed, or otherwise fails, a redundant communication path among thehub controllers 1602, 1604 remains. Where the hub controllers 1602, 1604are embodied as depicted in FIG. 3, with an LCD screen or other displaycapable of displaying status information, they may act as individual,intelligent diagnostic points for the control network 1601.

In the control network 1601 of FIG. 16, or more generally the controlnetworks 100 or 200 illustrated in FIG. 1 or 2, the hubs and additionalnodes are arranged in a hierarchical architecture, with the higher tiernodes acting as masters for the lower tier slave nodes. Certain aspectsof a preferred communication protocol will now be described with respectto the more general control network diagram of FIG. 2, but it should beunderstood that the principles will be applicable to a variety of morespecific network implementations as well.

In various preferred embodiments, the master hub 202 and slave hubs 204communicate using a time division multiplexing technique, such as apolling technique. The master hub 202 may, for example, broadcastinformation among the slave hubs 204, which respond with the informationrequested, or else may carry out commands issued by the master hub 202.Within each hub 202, 204, the hub master node 232 or 252 broadcastsinformation to the various hub slave nodes 234 or 254 over an internalbus 235 or 255, and the hub slave nodes 234 or 254 likewise respond withthe information requested, or else carry out the commands issued by thehub master node 232 or 252. This same protocol is repeated for each ofthe lower-tier buses 215 and the nodes 214 connected thereto, with thehub slave nodes 254 acting as the master nodes with respect to thelower-tier buses. In this manner, hierarchical control may be readilyachieved.

While the control network 200 is not limited to any particularcommunication protocol or technique, it may be advantageous in certainembodiments for the internal buses 235, 255 to comprise high-speedparallel buses, as they may be contained entirely within a hubcontroller, while the additional buses 215 may be serial buses comprisedof, e.g., fiber optic lines. The hub master nodes 232 or 252 may therebycommunicate with the hub slave noes 234 or 254 at high speed, while thehub slave nodes 234 or 254 communicate with their respective lower-tiernodes 214 according to a serial communication protocol, such as an RS485 protocol. The individual buses 215 may communicate at differentrates, such as 9 kB or 24 kB, for example.

The control network 200 may also have more than a single master hub ornode at each tier, sharing concurrent control over the slave hubs ornodes. In such a case the master hubs or nodes may alternate or rotatecommunications with particular subsets of slave hubs or nodes. Uponfailure of one master hub or node, the other may take over itsresponsibilities, thus providing backup master control capability. Also,as an alternative to time division multiplexing, or in addition thereto,the hubs or nodes may communicate using, e.g., different transmissionwavelengths, thus allowing concurrent transmissions withoutinterference, and/or may encode their transmissions using spreadspectrum techniques (thereby utilizing a form of code divisionmultiplexing).

Certain communication techniques that may be particularly well suitedfor communication in a ring or loop architecture, and applicable tovarious control network configurations described herein, will now bedescribed with respect to FIGS. 18-20. The description of FIGS. 18-20focuses more on the communication protocol, and omits detailsconcerning, e.g., distribution of power among nodes or to various loads.Also, the description pertaining to FIGS. 18-20 occasionally refersgenerically to “nodes,” which in this case encompasses hubs within itsmeaning. Additional details concerning techniques for communication in amaster-slave control network environment, as may be used in connectionwith the various embodiments as described herein, are explained indetail in copending U.S. patent application Ser. No. 10/193,714 filedJul. 10, 2002, assigned to the assignee of the present invention, andhereby incorporated by reference as if set forth fully herein.

FIG. 18 is a block diagram of a network node 1800 according to oneembodiment as disclosed herein, as may be utilized, for example, in thecontrol networks of FIG. 1 or 2 (as, e.g., either a master node or aslave node). In FIG. 18, the network node 1800 comprises an opticalreceiver 1812 connected to one branch 1802 of an optical fiber of thering network, and an optical transmitter 1813 connected to anotherbranch 1803 of the optical fiber of the ring network. The opticalreceiver 1812 and optical transmitter 1813 are shown connected to aprocessor 1820, which may comprise, e.g., a microprocessor ormicrocontroller having suitable processing speed and data throughput tohandle the functions to be carried out by the network node 1800. Theprocessor 1820 is shown connected to a memory 1825, which preferablycomprises a non-volatile portion (such as, e.g., ROM, PROM, EPROM,EEPROM, or flash ROM) and a volatile portion (e.g., RAM). Thenon-volatile portion of the memory 1825 may store programminginstructions which are executed by the processor 1820 and therebycontrol the general operation of the network node 1800. The processor1820 may also be connected to a plurality of I/O ports 1830, allowingthe network node 1800 to interface with one or more external components.Examples of such external components include sensors, lights, switches,actuators, and so on.

In operation, the network node 1800 receives data from the fiber branch1802 attached to the optical receiver 1812, processes the data usingprocessor 1820 and/or stores the data, or other data generated inresponse thereto, in the volatile portion of the memory 1825, and, ifthe protocol calls for it, transmits data via the optical transmitter1813 onto the fiber branch 1803.

In one or more embodiments, the network node 1800 directly passesthrough data from the optical receiver 1812 to the optical transmitter1813, optionally with some level of processing. In a preferredimplementation, the optical receiver 1812 converts optical data toelectrical data, processes the electrical data, and passes the processedelectrical data to the optical transmitter 1813, whereupon it isre-converted to optical data and transmitted over a fiber or otheroptical connection. When the data is in electrical form, it can beexamined to determine, for example, whether the communication isintended for the particular node 1800, whether errors are present, andso on. In one example, if the network node 1800 receives a communicationvia optical receiver 1812 having errors associated with it, the networknode 1800 adds an error code to the communication as it passes it along,via the optical transmitter 1813, for the next node. An error code mayindicate, for example, that the communication received from the upstreamnode was not in an expected format, failed a cyclic redundancy check(CRC) or other error check, failed to contain an expected field or itemof information, arrived at an unexpected time, or any other statuscondition. A master node or other downstream node in the control networkmay then use the error information to determine problems with thecontrol network.

To facilitate reporting of status conditions using error codes, thecontrol network in which the network node 1800 is utilized may employ acommunication protocol in which messages exchanged among the variousnodes have a pre-designated format which provides for the inclusion ofan error code. The error code may, for example, be inserted in adesignated location in the message, or else may be appended to themessage. If desired, multiple error codes may be added to a message frommultiple network nodes in the control network. The network node 1800 maybe configured to add a new error code to a received message only if itdetects an error different in nature from the error(s), if any,indicated by any existing error code(s) already included with thereceived message (as may have been added by a network node upstream inthe control network, for example).

In certain alternative configurations of network node 1800, the networknode 1800 may utilize an add/drop multiplexer in place of the opticalreceiver 1812 and optical transmitter 1813. A variety of add/dropmultiplexer designs are known in the art of optical communication, and adetailed description thereof is not deemed necessary.

As another alternative, the optical receiver 1812 and opticaltransmitter 1813 may each be replaced with an optical transceiver,thereby providing the network node 1800 with bidirectional communicationcapability and, therefore, the ability to support bidirectionalcommunication in the fiber optic ring network.

FIG. 19 is a block diagram of a network node 1900 according to anotherembodiment as disclosed herein, adapted for use in a two fiber ringnetwork (such as shown conceptually in, e.g., FIG. 8A, described ingreater detail hereinafter). In FIG.

19, the network node 1900 includes two optical receivers 1912, 1915 andtwo optical transmitters 1913, 1917. The first optical receiver 1912 andoptical transmitter 1917 are associated with the first fiber optic loop(designated the “A loop”), while the second optical receiver 1915 andoptical transmitter 1913 are associated with the second fiber optic loop(designated the “B loop”). The first optical receiver 1912 has an outputconnected to the first optical transmitter 1917, to permit propagationof signals around the A loop. The second optical receiver 1915 has anoutput connected to the second optical transmitter 1913, likewise topermit propagation of signals around the B loop. Both optical receivers1912, 1915 have outputs connected to a receive arbiter 1950, which, aswill be explained, selects between data from optical receivers 1912,1915 for further processing. Both optical transmitters 1913, 1917 arepreferably driven by a synchronizing driver 1955. In the particularexample illustrated in FIG. 19, the network node 1900 comprises twoprocessors 1920, 1940, one of which (processor 1920 in this example)serves as the primary processor, and the other of which (processor 1940in this example) serves as a backup processor in case the primaryprocessor fails. A fault detector 1960 may be communicatively connectedto both the processors 1920, 1940, allowing detection of faults by anyof the means as described elsewhere herein. The fault detector 1960 isdepicted in a conceptual manner and may represent actual hardware orelse may simply represent functionality that is built in to the node'ssoftware instructions, or any combination thereof. For example, thefault detector may comprise, e.g., a watchdog timer, a softwareverification routine for periodically testing the integrity of thenetwork ring, or any other hardware or software that can be used todetector a fault condition. Both processors 1920, 1940 are alsopreferably communicatively connected to a plurality of I/O ports 1930,allowing the processors 1920, 1940 to communicate with externalcomponents over various input/output signal lines 1935.

In certain embodiments, as explained later herein, the network node 1900optionally may provide communication capability on a second ring ofnetwork nodes. The network node 1900 may have the capability of actingboth as a slave and a master—i.e., a slave with respect to a first ringof network nodes, and a master with respect to a second ring of networknodes. Both the first ring and the second ring may comprise a pair offiber optic cables for bidirectional communication in each ring. In suchan embodiment, both processors 1920, 1940 of the network node 1900 mayeach comprise two processing units, labeled as “CNET” and “DNET” in theinstant example, and the network node 1900 may further include a secondset of transmit/receive optical components for communicating on thesecond ring (as illustrated in, e.g., FIG. 19). The CNET processing unit1921 (or 1941), acting in a slave capacity, receives and responds tocommunications from a first network ring, while the DNET processing unit1922 (or 1942), acting in a master capacity, transmits commands andreceives feedback from slave nodes in the second network ring. Asexplained hereinafter, such a capability in the network node 1900 isparticularly well suited for a hierarchical master-slave controlnetwork.

In operation, the network node 1900 is capable of receiving data on bothloops A and B, and transmitting data simultaneously over both loops Aand B. Because of differences in propagation delay times depending uponwhere the network node 1900 is situated in the ring network, the receivearbiter 1950 performs the task of determining which data (the A loopdata or B loop data) should be utilized for further processing.

According to a preferred embodiment, the receive arbiter 1950 does thisby determining which loop data arrived first in time. The first arrivingdata is processed, while the second arriving data may be used to confirmthe accuracy of the first arriving data, or else may be discarded.

Various possible circuits for receive arbiter, as may be used in thenetwork node 1900 illustrated in FIG. 19, are illustrated in copendingU.S. patent application Ser. No. 10/193,714 filed Jul 10, 2002, assignedto the assignee of the present invention, and hereby incorporated byreference as if set forth fully herein. Other circuitry (e.g., aprocessor) in a network node may utilize the NB arrival status, as wellas other information (such as error status), to select between A-loopdata and B-loop data for further processing. Other approaches toselecting between A-loop data and B-loop data may also be used.

Further explanation will now be provided concerning the operation ofvarious control networks in which two fibers (A-loop and B-loop) areemployed for bidirectional communication. FIG. 20 is a diagramillustrated a relatively simple example of a master-slave ring network2000 having two fibers, and showing certain node details. In FIG. 20, amaster node 2002 (which in this example is embodied as a network node1900 such as described with respect to FIG. 19) and two slave nodes 2004are connected by two fibers 2005 (A-loop) and 2006 (B-loop) in a ringconfiguration. While two slave nodes 2004 are illustrated in FIG. 20,any number of slave nodes 2004 may be present.

As with the network node 1900 illustrated in FIG. 19, the master node2002 preferably comprises two optical receivers 2012, 2015 and twooptical transmitters 2013, 2017. The first optical receiver 2012 andoptical transmitter 2017 are associated with the first fiber optic loop(the “A loop”) 2005, while the second optical receiver 2015 and opticaltransmitter 2013 are associated with the second fiber optic loop (the “Bloop”) 2006. In certain embodiments, for example where multiple masternodes exist or where slave nodes have backup master node functionality,then the optical receivers 2012, 2015 may provide the capability ofpassing through data directly to the optical transmitters 2013, 2017. Insuch an embodiment, the first optical receiver 2012 may have an output(not shown) connected to the first optical transmitter 2017 to permitpropagation of signals around the A loop, and the second opticalreceiver 2015 may likewise have an output (not shown) connected to thesecond optical transmitter 2013 to permit propagation of signals aroundthe B loop.

Both optical receivers 2012, 2015, similar to the network node 1900 inFIG. 19, preferably have outputs connected to a receive arbiter 2050which, as previously explained, selects between data from opticalreceivers 2012, 2015 for further processing. Both optical transmitters2013, 2017 may be simultaneously driven by a synchronizing driver 2055.In the particular example illustrated in FIG. 20, the master node 2002comprises two processors 2020, 2040, one of which serves as the primaryprocessor and the other of which serves as a backup processor in casethe primary processor fails. A fault detector 2060 is communicativelyconnected to both the processors 2020, 2040, allowing detection offaults as further described herein.

The slave nodes 2004 in the example of FIG. 20 each comprise a twooptical receivers 2062, 2065 and two optical transmitters 2063, 2067.The first optical receiver 2062 and first optical transmitter 2067 areassociated with the first fiber optic loop (the “A loop”) 2005, whilethe second optical receiver 2065 and second optical transmitter 2063 areassociated with the second fiber optic loop (the “B loop”) 2006. Theoptical receivers 2062, 2065 preferably pass through data directly tothe optical transmitters 2063, 2067. Accordingly, the first opticalreceiver 2062 has an output connected to the first optical transmitter2067 to permit propagation of signals around the A loop 2005, and thesecond optical receiver 2065 likewise has an output connected to thesecond optical transmitter 2063 to permit propagation of signals aroundthe B loop 2006. Both optical receivers 2062, 2065 preferably haveoutputs connected to a receive arbiter 2060 which selects between datafrom optical receivers 2062, 2065 for further processing. Both opticaltransmitters 2063, 2067 are driven by a synchronizing driver 2075.

The master node 2002 may communicate with the slave nodes 2004 accordingto any desired protocol. In a preferred embodiment, the master node 2002polls the slave nodes 2004 periodically, according to, for example,graph 202 shown in FIG. 2, or according to any other suitable protocol.

When transmissions occur from the master node 2002 to the slave nodes2004, the master node 2002 preferably transmits on both the A-loop 2005and the B-loop 2006 simultaneously, but in opposite directions (asindicated by the arrows in FIG. 20). The synchronizing driver 2055ensures that the transmissions on both the A-loop 2005 and the B-loopoccur simultaneously. However, in certain embodiments, it may bedesirable to gate the output of the synchronizing driver 2055 orotherwise make its output selectable, so that the integrity of theA-loop 2005 and the B-loop 2006 can be separately and independentlytested. The same would be true for the slave nodes 2004 where it ispossible for the slave nodes 2004 to take over the functionality of themaster node 2002 in the case of a master node failure.

The first slave node 2004 in the “clockwise” direction, i.e., “Slave-1”in this example, directly receives the transmission from opticaltransmitter 2017 of the master node 2002 on the A-loop 2005, while thefirst slave node 2004 in the “counter-clockwise” direction, i.e.,“Slave-2” in this example, directly receives the transmission fromoptical transmitter 2013 of the master node 2002 on the B-loop 2006.Slave-1 immediately propagates the received signal on the A-loop 2005from the A-loop receiver 2062 to the A-loop transmitter 2067, whereuponthe message is carried forward to Slave-2 on the A-loop 2005. Likewise,Slave-2 immediately propagates the received signal on the B-loop 2006from the B-loop receiver 2065 to the B-loop transmitter 2063, whereuponthe message is carried forward to Slave-2 on the B-loop 2006. Similarly,Slave-1 immediately propagates the received signal on the B-loop 2006from the B-loop receiver 2065 to the B-loop transmitter 2063, whereuponthe message is carried forward to the master node 2002 on the B-loop2006, thus allowing the B-loop message to make a complete loop, andSlave-2 immediately propagates the received signal on the A-loop 2005from the A-loop receiver 2062 to the A-loop transmitter 2067, whereuponthe message is carried forward to the master node 2002 on the A-loop2005, thus allowing the A-loop message to make a complete loop.

If any additional slave nodes 2004 were present, the A-loop messagewould be propagated in a “clockwise” direction from slave node to slavenode in the same manner until eventually reaching the master node 2002on the A-loop 2005, and the B-loop message would be propagated in a“counter-clockwise” direction from slave node to slave node in the samemanner until eventually reaching the master node 2002 on the B-loop2006.

At each slave node 2004, assuming no breakages on the transmissionfibers or other disruptions to communication, a message will be receivedon both the A-loop 2005 and the B-loop 2006. Each slave node 2004selects one of the two messages for further processing (or a combinationof the two if errors are present but a complete message can bereconstructed from both receptions), and the slave node 2004 thendetermines whether the message from the master node 2002 was intendedfor the particular slave node and/or if a response is required.Selection between the two messages can be based upon the first arrivingmessage (using an arbiter circuit such as described with respect toFIGS. 14, 15A, and 16), the number of errors in the received messages(if any), or a combination of the two. If a response to the receivedmessage is required, then, at a prescribed interval dictated by theparticular communication protocol in use, the slave node 2004 respondswith a return message transmitted via the synchronizing driver 2075 andoptical transmitters 2063, 2067 over both the fibers 2005, 2006.

The return message from each slave node 2004 is propagated in both a“clockwise” and “counter-clockwise” direction by virtue of the twofibers 2005, 2006. For example, a return message transmitted by thefirst slave node 2004 (Slave-1) will propagate in a “clockwise”direction around the A-loop fiber 2005, via the second slave node 2004(Slave-2) to the master node 2002. The return message will propagate ina “counter-clockwise” direction around the B-loop fiber 2006 to themaster node 2002. The master node 2002 will receive the return messageon both the A-loop fiber 2005 and B-loop fiber 2006, through opticalreceivers 2015 and 2012, respectively. The return message, in thisparticular example, is conveyed to a receive arbiter circuit 2050, whichmakes a decision as to which version of the return message (orcombination of the two versions) to utilize for further processing.

A similar type of operation occurs for a message transmitted by themaster node 2002 to the Slave-2 slave node 2004, and a return messagetransmitted by the Slave-2 slave node 2004 back to the master node 2002.In other words, the master node message is transmitted in oppositedirections along both fibers 2005, 2006 from the master node 2002 to theSlave-2 slave node 2004, and the return message is transmitted inopposite directions along both fibers 2005, 2006 from the Slave-2 slavenode 2004 back to the master node 2002. When the receiving slave node2004 (either Slave-1 or Slave-2) receives a master node message intendedfor it, which is not a broadcast message intended for multiple slavenodes 2004, the receiving slave node 2004 may, in certain embodiments,be configured such that the slave node 2004 does not propagate themessage any further around the loop. However, in a preferred embodiment,the slave node 2004 propagates the master node message around theremainder of the loop until the master node 2002 receives its ownmessage back at its receiver 2012 or 2015. Among other things, thisapproach assists the master node 2002 in detecting fault conditions.

The format of master node and slave node messages transmitted within thenetwork 2000 depend upon the particular type of network, protocol, andother such factors. For example, a message may comprise a series of databits divided into various fields, and may be encoded, if desired, forsecurity, error detection/correction, or other such purposes. Accordingto one example, for instance, a master node message format includes oneor more start delimiter data bits, a node identification field (andoptionally additional message header fields), a master data messagefield, and one or more stop delimiter data bits; and the slave nodemessage format includes a slave data message field a messageauthentication code (“MAC”) or other integrity code, and, optionally,one or more header fields as well. Also, optionally, the slave nodemessage format may include a variable-length error field in which aslave node 2004 can inject an error code indicating the type of observederror/fault and the location of the error (e.g., a node identification).The slave node 2004 may inject the error code when a master node messageor slave node message is being propagated through the slave node 2004.The error code may indicate, by way of example, that the slave node 2004did not receive a complete message, that it observed errors in the databits or authentication code, that the signal strength from the precedingnode was weak, and other types of conditions which may be of use to themaster node 2002.

In its response message, the slave node 2004 can also include varioustypes of error codes. By way of example, the slave node 2004 mayindicate in its return message to the master node 2002 that it failed toreceive the master node message on both the A-loop 2005 and the B-loop2006. The master node may use such information to identify and locatefaults in either or both of the loops 2005, 2006. The ring architecturemay provide various advantages in terms of detecting faults and locatetheir proximity within the network. A fault may occur, for example,where a node's processor fails, or where one or more of its receivers ortransmitters fail. Most of these situations will manifest by the failureof a message to be propagated around the network ring on one or both ofthe optical fibers. A fault may also occur where the fiber is physicallydamaged such that a transmission is degraded beyond a tolerable level.

In various embodiments, it may be desirable to provide slave nodes whichserve a secondary functionality as a master node in case of failure bythe master node, thereby increasing the redundancy and reliability ofthe overall network. Failure of the current master node commonly resultsin the master node either failing to transmit, or else transmittingimproper control information to the slave nodes. According to apreferred redundant backup control protocol, the slave nodesperiodically receive master-control messages from the master node and,in the event that proper master-control messages fail to appear,initiate a failure mode response procedure.

In operation, in accordance with one embodiment, the slave nodes S1, S2,. . . monitor the A loop and B loop while in a “listen” mode and awaitperiodic master node messages from the master node M. Upon a failure toreceive a transmission from the master node M on either the A loop or Bloop within an expected time interval from a previously observedtransmission, the slave nodes S1, S2, . . . begin to time a wait period(which, as described in more detail below, is preferably a differentwait period for each slave node in the network). When the wait periodelapses, the slave node determines that a failure in the master node forthe particular data bus has occurred, and takes steps to take over thefunctionality of the master node.

Each of the slave nodes is preferably programmed with a different waitperiod, so that no contention occurs for replacing the master node Mwhen a master node failure has occurred. In one aspect, backup controlof each master node is prioritized, such that there is a specific orderin which the slave nodes can potentially take over control of the masternode functionality when a failure has occurred.

Each of the nodes (master and slave) may be provided with hardwarecomponents that facilitate operation in a network having redundantbackup master capability. Each of the nodes, for example, may comprisean uplink mode processor and a downlink mode processor. With particularreference to, e.g., FIG. 19, each of the nodes may comprise an uplinkmode processor such as “DNET” 1922 (or 1942 if provided with an internalbackup processor or processors) and a downlink mode processor such as“CNET” 1921 (or 1941 if provided with an internal backup processor orprocessors). The “CNET” processor 1921 and “DNET” processor 1922 maycomprise, e.g., co-processors which collectively form a portion ofprocessor 1920, in addition to the supporting circuitry such as RAM(which may be dual-port in nature), ROM, and other digital components asmay be provided. The downlink or “CNET” processor 1921 acts as a“master” processor and controls the other nodes in the network. Theremay be one master node or multiple master nodes in a particular ringnetwork, but if multiple master nodes are present then each master nodepreferably controls a distinct subset of slave nodes. The uplink or“DNET” processor 1922 acts as a “slave” processor and responds to amaster node in the ring network.

A master node may, in certain embodiments, utilize its downlink or“CNET” processor 1921 to control the slave nodes S1, S2, and S3. Theslave nodes S1, S2, and S3 would receive, process, and respond to masternode messages using their uplink or “DNET” processor. (Both the “CNET”and “DNET” processors 1921, 1922 and 1941, 1942 connect or have accessto the A loop and B loop). Upon a failure of the master node, asdetected by, e.g., a timeout of a predetermined wait period, then one ofthe slave nodes (for example, S1) takes over as the new effective masternode. The slave node S1 then employs its downlink processor “CNET” 1921to control the other two slave nodes S2 and S3. The slave node S1 maycontinue to transmit messages to its own uplink transceiver “DNET” 1922so that slave node S1 can continue to carry out its former duties priorto the master node failure, or else it can control itself internally tocontinue to carry out those duties.

In a preferred embodiment, detection of a master node failure conditionis accomplished using an internal timer mechanism, such as a hardware orsoftware timer accessible (either directly or indirectly) by the uplinkprocessor “DNET” 1922. Under a particular configuration, the slave nodereceives master node messages periodically from the master node M. Themaster node M may thereby, for example, request status information fromthe slave node, or instruct the slave node to carry out certain controlor input/output functions. The slave node ordinarily responds bycarrying out the requested functions and/or sending an acknowledgment orstatus signal to the master node M using the uplink processor “DNET”1922. The internal timer mechanism of the slave node times out a waitperiod between master node messages received from the master node M.Each time the uplink processor “DNET” 1922 detects a master node messagefrom the master node M that is recognized as an appropriate master nodemessage within the particular programmed control protocol (whether ornot the master node message is directed to the particular slave node),the uplink processor “DNET” 1922 resets the internal timer mechanism. Ifthe internal timer mechanism ever times out, then the uplink processor“DNET” 1922 responds by asserting a failure mode response procedure. Thetiming out of the internal timer mechanism may result in an interrupt todownlink processor “CNET” 1921 in order to inform the downlink processor“CNET” 1921 of a perceived master node failure, or else, for example,the downlink processor “CNET” 1921 may periodically monitor the internaltimer mechanism and commence a failure mode response procedure when itobserves that the timer has timed out, or else the uplink processor“DNET” 1922 may set a flag in a dual port RAM (not shown) which ischecked periodically by the downlink processor “CNET” 1921.

When the downlink processor “CNET” 1921 has been informed or otherwisedetermined that a failure mode condition exists, and that the masternode M has presumably failed, the downlinkg processor “CNET” 1921 takesover as the new effective master node. When the failure mode is entered,the downlink transceiver “CNET” 1921 may be programmed so as to directlycarry out the I/O port functions for which it previously receivedinstructions from the first-tier master node, or the node may sendmaster control messages to its own uplink processor “DNET” 1922, eitherexternally via the A loop and/or B loop or internally via the dual portRAM or other means, and thereby continue to carry out the I/O portfunctions or other functions as it had previously been doing. In otherwords, the node can give itself control instructions so that it cancontinue to perform its previously assigned functions. If, after takingover for the master node M, the slave node's downlink processor “CNET”1921 should fail, the node can still continue to perform its assignedfunctions when the next slave node S2 takes over control as the neweffective master node, because its uplink processor “DNET” 1922 maycontinue to function in a normal manner in a slave mode.

According to the foregoing technique, a given slave node therebysubstitutes itself for the master node M upon the detection of a masternode failure as indicated by the failure to receive the expected masternode control messages.

The order in which the slave nodes S1, S2, . . . take over for themaster node M may be dictated by the wait period timed by the internaltimer mechanism of the particular slave node. The internal timermechanism for each slave node is preferably programmed or reset with adifferent time-out value. A given slave node only asserts a failure modecondition when its internal timer mechanism reaches the particulartimeout value programmed for that particular node.

The foregoing techniques thereby may provide redundant backup for themaster node M in a control network, without necessarily requiring, forexample, additional physical nodes to be located within the controlnetwork, and without having to provide wiring for such additionalphysical nodes to the optical loops A and/or B. The redundant backup forthe master node M is also accomplished in a manner resolving potentialcontention problems that might otherwise occur if more than one theslave nodes detected a master node failure and simultaneously attemptedto take control as effective master of the control network.

The architecture illustrated in FIGS. 1, 2 and 16 can be extrapolated toany number of tiers, and is not limited to three tiers. For example,each of the nodes 114, 214 or 1614 may control a lower-tier network, ifdesired.

The various ring networks described herein may be designed according toany of a variety of signaling protocols, including the SONET(Synchronous Optical Network) signal hierarchy. The SONETprotocol/hierarchy defines a family of digital signals having bit ratewhich are integer multiples of a basic module signal, referred to as theSynchronous Transport Signal Level 1 (STS-1). The basic module signal isformed from a sequence of repeating frames, each of which includes a setnumber of bytes (e.g., eight bytes). Some of the bytes are reserved foroverhead, while the remaining ones are available for data transport. Adetailed explanation of the SONET protocol/hierarchy is not deemednecessary because such details are widely available and well known inthe art.

The various network nodes as described herein may be constructed in anysuitable manner and may, for example, comprise circuitry and variouselectronics housed in a rugged, potted case made of a suitablelightweight material such as aluminum that provides environmentalprotection and allows for heat dissipation. In other types of controlenvironments, different types of housings or constructions may be used.

Many of the embodiments described herein will find particularapplicability in on-board vehicle control systems. In this context, theterm “vehicle” is used broadly to include any conveyance, including, byway of example, trains, buses, railcars, automobiles, trucks, ships,airplanes, tanks, and military vehicles.

The various embodiments described herein can be implemented using eitherdigital or analog techniques, or any combination thereof. The term“circuit” as used herein is meant broadly to encompass analogcomponents, discrete digital components, microprocessor-based or digitalsignal processing (DSP), or any combination thereof. The invention isnot to be limited by the particular manner in which the operations ofthe various embodiments are carried out.

While certain system components are described as being “connected” toone another, it should be understood that such language encompasses anytype of communication or transference of data, whether or not thecomponents are actually physically connected to one another, or elsewhether intervening elements are present. It will be understood thatadditional circuit or system components may be added to the variousillustrated or described embodiments without departing from teachingsprovided herein.

Various embodiments have been described herein in which two fibers areused for communication in the context of, e.g., a ring network system;however it will be appreciated that additional fibers can also be usedin the ring network to, e.g., increase bandwidth or provide addedredundancy. In addition, throughput may also be increased bytransmitting at multiple distinct optical wavelengths (i.e., color orwavelength division multiplexing). A variety of techniques for color orwavelength division multiplexing are known in the art and therefore adetailed explanation thereof is not deemed necessary herein.

While preferred embodiments of the invention have been described herein,many variations are possible which remain within the concept and scopeof the invention. Such variations would become clear to one of ordinaryskill in the art after inspection of the specification and the drawings.The invention therefore is not to be restricted except within the spiritand scope of any appended claims.

1. (canceled)
 2. A network node for use in a control network,comprising: a pair of housing shellplates adapted to form an outerhousing shell when attached together with a hollow interior regiondefined within the outer housing shell, wherein said housing shellplatesfurther define at least one narrow recess where the shellplates meet,with each housing shellplate constituting a top or bottom wall of therecess; a circuitboard oriented transversely within the hollow interiorregion of the outer housing shell with respect to the recess; and apower transistor disposed within a package and mounted on saidcircuitboard, said package having a distal end furthest away from saidcircuit board, wherein the distal end of the power transistor packageresides within the recess so as to contact at least one of the housingshellplates defining the recess.
 3. The network node of claim 2, whereinthe housing shellplates are semi-cylindrical, and when attached togetherthe housing shellplates form a cylindrical outer housing shell.
 4. Thenetwork node of claim 2, wherein the outer housing shell comprisesheat-dissipating fins on an outer surface thereof.
 5. The network nodeof claim 4, wherein the housing shellplates are metallic.
 6. The networknode of claim 5, wherein the power transistor releases heat throughcontact with at least one of the metallic housing shellplates, wherebythe heat is conveyed to said heat-dissipating fins.
 7. The network nodeof claim 2, further comprising a first connector for receiving one ormore data lines and a high power supply signal, and a second connectorfor attaching to control lines controlling one or more local devices ina vehicle.
 8. The network node of claim 7, wherein the outer housingshell forms a tube-like shape with two opposite ends, with a firsthousing sidewall capping one end of the outer housing shell, and asecond housing sidewall capping the other end of the outer housingshell.
 9. The network node of claim 8, wherein said first connectorresides on the first housing sidewall, and wherein said second connectorresides on the second sidewall, such that the data lines and high powersupply signal enter and the control lines exit from opposite ends of theouter housing shell.
 10. The network node of claim 7, wherein said powertransistor is configured to selectively couple high power to one of saidlocal devices in the vehicle.
 11. The network node of claim 8, whereinsaid housing shellplates further define a second narrow recess where theshellplates meet and opposite the at least one narrow recess, with eachhousing shellplate constituting a top or bottom wall of the secondrecess, the network node further comprising a second power transistordisposed within a second package and mounted on a back side of saidcircuitboard, said second package having a distal end furthest away fromthe back side of said circuit board, wherein the distal end of thesecond power transistor package resides within the second recess so asto contact at least one of the housing shellplates defining the secondrecess.
 12. The network node of claim 2, further comprising at least oneprocessor for managing communications with an upstream network node viaelectrical signals transmitted over the data lines.
 13. The network nodeof claim 12, wherein said at least one processor further generatescommands for controlling the one or more local devices via the controllines.
 14. The network node of claim 13, wherein said at least oneprocessor is disposed on said circuitboard.
 15. The network node ofclaim 2, further comprising a plurality of light-emitting diodes (LEDs)disposed on said circuitboard and protruding from apertures formed inthe outer housing shell.
 16. The network node of claim 15, wherein saidLEDs provide visible status indications under control of said at leastone processor.
 17. A network node for a control network within avehicle, the network node comprising: an outer housing; a circuitboarddisposed within the housing; a first bus connector coupled to one ormore data lines from an upstream network node and for receiving a highpower input signal derived from a vehicle battery; a second busconnector coupled via control lines to one or more external localdevices associated within the vehicle under control of the network node;and at least one processor disposed on said circuitboard forcommunicating with the upstream network node by transmitting andreceiving signals over the data lines coupled to the first busconnector, and for controlling the external local devices throughcommands transmitted over the control lines.
 18. The network node ofclaim 17, wherein said data lines and high power input signal aretransported on a common cable that couples to said first bus connector.19. The network node of claim 17, wherein said outer housing comprises apair of housing shellplates which define a hollow interior region whenattached together to form at least part of the outer housing.
 20. Thenetwork node of claim 19, wherein said housing shellplates furtherdefine at least one narrow recess where the shellplates meet, with eachhousing shellplate constituting a top or bottom wall of the recess. 21.The network node of claim 20, wherein the outer housing comprisesheat-dissipating fins on an outer surface thereof.
 22. The network nodeof claim 20, wherein the circuitboard is oriented transversely withinthe hollow interior region of the outer housing with respect to therecess.
 23. The network node of claim 22, further comprising a powertransistor disposed within a package and mounted on said circuitboard,said package having a distal end furthest away from said circuit board,wherein the distal end of the power transistor package resides withinthe recess so as to contact at least one of the housing shellplatesdefining the recess.
 24. The network node of claim 23, wherein thehousing shellplates are metallic.
 25. The network node of claim 23,wherein the power transistor releases heat through contact with at leastone of the metallic housing shellplates, whereby the heat is conveyed tosaid heat-dissipating fins.
 26. The network node of claim 19, whereinthe housing shellplates are semi-cylindrical, and when attached togetherthe housing shellplates form a cylindrical outer housing shell.
 27. Thenetwork node of claim 19, wherein the outer housing shell forms atube-like shape with two opposite ends, with a first housing sidewallcapping one end of the outer housing shell, and a second housingsidewall capping the other end of the outer housing shell.
 28. Thenetwork node of claim 27, wherein said first bus connector resides onthe first housing sidewall, and wherein said second bus connectorresides on the second sidewall, such that the data lines and high powerinput signal enter and the control lines exit from opposite ends of theouter housing shell.
 29. The network node of claim 17, furthercomprising a plurality of light-emitting diodes (LEDs) disposed on saidcircuitboard and protruding from apertures formed in the outer housing.30. The network node of claim 29, wherein said LEDs provide visiblestatus indications under control of said at least one processor.
 31. Amethod for constructing a network node for use in a control network,comprising: attaching a pair of housing shellplates to form an outerhousing shell with a hollow interior region defined therein, whereinsaid housing shellplates further define at least one narrow recess wherethe shellplates meet, with each housing shellplate constituting a top orbottom wall of the recess; disposing a circuitboard transversely withinthe hollow interior region of the outer housing shell with respect tothe recess; and mounting a power transistor package on saidcircuitboard, said power transistor package having a distal end furthestaway from said circuit board, such that the distal end of the powertransistor package resides within the recess so as to contact at leastone of the housing shellplates defining the recess.
 32. The method claim31, wherein the outer housing shell comprises heat-dissipating fins onan outer surface thereof.
 33. The method of claim 32, wherein thehousing shellplates are metallic.
 34. The method of claim 33, whereinduring operation the power transistor package releases heat throughcontact with at least one of the metallic housing shellplates, wherebythe heat is conveyed to said heat-dissipating fins.
 35. The method ofclaim 31, further comprising providing a first connector for the networknode for receiving one or more data lines and a high power supplysignal, and providing a second connector for the network node forattaching to control lines controlling one or more local devices in avehicle.
 36. The method of claim 35, wherein the outer housing shellforms a tube-like shape with two opposite ends, further comprisingplacing a first housing sidewall to cap one end of the outer housingshell, and placing a second housing sidewall to cap the other end of theouter housing shell.
 37. The method of claim 36, wherein said firstconnector resides on the first housing sidewall, and wherein said secondconnector resides on the second sidewall, such that the data lines andhigh power supply signal enter and the control lines exit from oppositeends of the outer housing shell.
 38. The method of claim 31, furthercomprising disposing at least one processor on said circuitboard formanaging communications with an upstream network node via electricalsignals transmitted over the data lines, and for generating commands tocontrol the one or more local devices via the control lines.
 39. Themethod of claim 31, further comprising disposing a plurality oflight-emitting diodes (LEDs) on said circuitboard and protruding fromapertures formed in the outer housing shell so as to provide visiblestatus indications.
 40. A method for control and power distribution viaa network node in a vehicle control network, comprising: coupling one ormore data lines from an upstream source to a first bus connector of thenetwork node; coupling a high power input signal to the first busconnector; coupling one or more control lines from a second busconnector of the network node to local devices in a vehicle; controllingor monitoring the local devices in the vehicle by generating andtransmitting commands from the network node to the local devices via thecontrol lines, in response to upstream commands received via the datalines, and receiving electrical signals from the local devices; andproviding high power to at least one of the local devices in the vehicleby selectively coupling the high power input signal to the local devicethrough a high power switch.
 41. The method of claim 40, wherein saiddata lines and high power input signal are transported on a common cablethat couples to said first bus connector.
 42. The method of claim 40,wherein the network node comprises a pair of housing shellplates formingan outer housing and defining a hollow interior region when attachedtogether.
 43. The method of claim 42, wherein said housing shellplatesfurther define at least one narrow recess where the shellplates meet,with each housing shellplate constituting a top or bottom wall of therecess.
 44. The method of claim 43, wherein the outer housing comprisesheat-dissipating fins on an outer surface thereof.
 45. The method ofclaim 44, wherein a circuitboard is disposed within the hollow interiorregion of the outer housing, and wherein at least one processor ismounted on said circuitboard.
 46. The method of claim 45, wherein thehigh power switch contained within a package mounted on saidcircuitboard, said package having a distal end furthest away from saidcircuit board, wherein the distal end of the package resides within therecess so as to contact at least one of the housing shellplates definingthe recess.
 47. The method of claim 46, wherein during operation thehigh power switch releases heat through contact with at least one of themetallic housing shellplates, whereby the heat is conveyed to saidheat-dissipating fins.
 48. The method of claim 45, wherein the at leastone processor controls the high power switch to selectively supply powerfrom the high power input signal to the local device.
 49. The method ofclaim 40, wherein said first bus connector resides on a first housingsidewall disposed at a first end of the outer housing, and wherein saidsecond bus connector resides on a second sidewall disposed at a secondend of the outer housing opposite said first end, such that the datalines and high power input signal enter and the control lines exit fromopposite ends of the outer housing shell.
 50. The method of claim 40,wherein said network node includes a plurality of light-emitting diodes(LEDs) for providing visible status indications.
 51. The method of claim40, wherein the high power input signal is derived from a vehiclebattery.